1. Technical Field
The present invention relates to a robot hand, a robot, and a holding method of holding an object to be pinched by the robot.
2. Related Art
Robots that hold objects to be pinched in assembling work, sorting work, or the like are utilized. Objects to be pinched that are intended to be held by the robots are various. A robot hand capable of holding objects having various shapes or high-hardness objects and flexible objects is disclosed in JP-A-2012-148380. According to JP-A-2012-148380, the robot hand includes a pair of supports. A bag body that is filled with a gel fluid is installed on one side of each support. When the supports sandwich an object to be pinched, the bag bodies are deformed along the shape of the object to be pinched. As a result, the robot hand can stably hold the object to be pinched.
In addition, a robot hand that holds objects to be pinched that are arranged side by side is disclosed in JP-A-9-103983. The robot hand includes a pair of finger-shaped bodies. The finger-shaped bodies are formed from a tubular soft material. Fingertip portions can be expanded by supplying a fluid to the fingertip portions of the finger-shaped bodies. The fingertip portions are expanded after inserting the thin fingertip portions into the gaps between adjacent objects to be pinched. As a result, the fingertip portions are stiffened. The robot hand holds the object to be pinched with the stiffened fingertip portions.
In the robot hand of JP-A-2012-148380, the pair of supports in which the bag bodies are installed hold the object to be pinched from both sides. When objects to be pinched are installed side by side, the supports in which the bag bodies are installed cannot be inserted between adjacent objects to be pinched unless the adjacent objects to be pinched are separated from each other.
In the robot hand of JP-A-9-103983, the side surfaces of the object to be pinched are held with the stiffened fingertip portions. Since the object to be pinched is held by a frictional force when the side surfaces of the object to be pinched are pressed, the surface state, hardness, and side surface shape of the object to be pinched are easily influenced. Accordingly, it is estimated that stable holding cannot be performed. Thus, a robot that stably holds an object to be pinched even when the gap between adjacent objects to be pinched is narrow is desired.